Automatic presser-foot-lifting mechanism.



PATENTED JUNE 16, 1908.

H. H. o'nmmmes. ,AUTOMATIG PRBSSBR FOOT LIFTING MECHANISM.

APPLICATION FILED JUNB'H. 1907.

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PATENTED JUNE 16, 1908.

No. 891,210. I

H. H. CUMMINGS. AUTOMATIC .PRESSER FOOT LIPTING MECHANISM.

' APPLICATION mm) mm: 11. 1901;

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o orne li Q'- Q d k UNITED STATES PATENT FFIOE.

HENRY H. CUMMINGS, OF NEWTON, MASSACHUSETTS, ASSIGNOR TO UNION LOCKSTITCH COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

AUTOMATIC PRESSER-FOOT-LIFTING ME CHANISM.

Original application filed August 19, 1904, Serial No. 221,378.

Specification of Letters Patent.

Patented June 16, 1908.

Divided and this application filed June 11, 1907.

Serial No. 378,394.

T 0 all whom it may concern:

Be it known that I, HENRY H. CUMMINGS, a citizen of the United States,residing at Newton, in the county of Middlesex, State of Massachusetts,have invented. a certain new and useful Improvement in AutomaticPresser-Foot-Lifting Mechanisms, of which the following isaspecification, reference be ing had therein to the accompanyingdrawings.

Sewing machines of certain classes are furnished with mechanismcomprising, essentially, a clamp cooperating with the presserbar of amachine, and actuating means for the said clamp acting in the operationof the machine to cause the clamp to grip or become engaged with thesaid presserbar and then move the latter in the direction of the lengththereof. Such mechanism is employed, for instance, for the purpose ofeffecting automatically the lifting of the presserfoot alternately withthe formation of the stitches in the working of a sewing machine. Thepresent invention has reference to mechanism of the general characteraforesaid.

It consists in the combination with the presser and presser-bar of asewing machine, or the like machine, of an improved clamp, and improvedclamp-operating means.

The invention is a division of that forming the subject of myapplication for United States Letters Patent for improvements in presserfoot lifting mechanism, filed August 19, 1904:, Serial No. 221,378, onwhich Letters Patent were granted July 2, 1907,

- No. 858,858, and in which the features of the clamp and its operatingmeans are claimed more broadly.

It will be explained with reference to the drawings, in which isillustrated an embodiment thereof, and in the course of the descriptionof the said embodiment the various objects and advantages thereof willbe set forth.

In the drawings,Figure 1 shows in end elevation the head of a sewingmachine having the said embodiment of the invention applied thereto.Fig. 2 is a view thereof mainly in vertical section in the planeindicated by the dotted line 2, 2, Fig. 1, looking in the directionindicated by the arrows at the ends of such line. Fig. 3 is a viewthereof mainly in vertical section in the plane indicated by the dottedline 3, 3, Fig. 1, looking in the direction indicated by the arrows atthe ends of such line. Fig. 4 is a view in horizontal section in theplane indicated by the dotted line 4, 4, Fig. 3, looking in thedirection indicated by the arrows at the ends of such line. Fig. 5 showsthe clamp-device separately in side elevation.

Having reference to the drawings,-a presser-bar is shown at 1, thepresser-foot at tached to the lower end thereof being indicated at 2.The presser-bar is mounted, as usual, in guide-bearings in the upper andlower portions of the head 3 of a sewing machine at the outer extremityof the arm or gooseneck 4 forming part of the frame of the said machine.To cause the presser-foot to bear against the material beneath the same,a depressing spring is applied in connection with the presser-bar, asusual. The depressing spring in the present instance is a spiralspring5, Figs. 1, 2 and 3. It is confined be tween a block or collar 6, fastupon the u per end of the presser-bar above the top 0 the head 3, and astationary upper collar 7. For the purpose of enabling the tension ofthe said depressing-spring 5 to be varied as required, in order toadjust the pressure of the presser-foot upon the material beneath it,the upper collar 7 is provided upon the lower end of a screw 8, thethreaded stem of the latter being fitted within an interiorlythreadedhole that is tapped through the horizontal arm of a bracket 9, the saidbracket being fixed to the head 3 and rising therefrom. By turning thescrew 8 in one direction or the other the collar 7 is lowered or raisedas may be necessary, and the tension of the spring is thereby varied inproportion as the spring 5 is compressed or relieved from compression.The screw 8 is provided with a lock-nut 81 to prevent accidental loss ofthe adjustment thereof. In order to prevent the presser-bar andpresser-foot from turning so as to swing the latter into an improperposition, the collar 6 is provided with an extension 61 that is slottedas indicated in Fig. 3 to fit the upright stem of the bracket 9. Thesaid slotted extension is free to slide up and down the said uprightstem, and hence the vertical movements of the presser-bar are notinterfered with, but lateral displacement of the presser-foot inconsequence of rotary movement of the presser-foot and presserbar aroundthe axis of the latter is obviated.

To assist in alining the screw 8 and collar 7 with the pr'esser-bar, andin preventing accidental shift horizontally of the horizontal arm ofbracket 9 by which said screw is carried, the opposite sides of theupright stem of the said bracket are flattened, as indicated at 91,Figs. 2 and 3, for engagement with the side-walls of the slot in theextension of collar 6. The lower end of the stem of bracket 9 isreceived in a socket 92 in the top of head 3, see Fig. 3, and removablysecured therein by means of a clamping-screw 93, Fig. 2. The looseningof the said clamping-screw, and removal of the bracket afi'ords opportunity to withdraw the presser-bar from its guide-bearings in head 3,after the disengagement of the presser-foot from the lower end of thepresser-bar. The parts thus far described, and the arrangement thereof,are not directly involved in the invention, and various changes may bemade therein in practice, if deemed desirable.

I will now proceed to describe the parts which are more immediatelyinvolved in the invention. A sleeve or block 10 is fitted upon thepresser-bar 1., within the opening at the outer end of the head 8, andbetween the upper and lower guide-bearings for the presser-bar in thesaid head. The said sleeve or block constitutes the body of the clampwhich I employ. It has a sliding fit upon the resser-bar, to enable thesleeve or block and presser-bar to move vertically with relation to eachother when not locked together. At one side of the sleeve or block aslot 101, Fig. 3, is formed through the wall thereof, the said slotextending vertically throughout the "reater portion of the length of thesleeve or b fock, and at opposite sides of the slot the sleeve or blockis formed or provided with rojecting-cheeks 102, 102, which are paralelwith each other. The cheeks receive between them lever-memberscomprising the clamping-lever 11 and the actuator-lever 12. The saidlever-members 11 and 12 respectively are provided with pivot-pins 111and 121, respectively, the bearings of which are constituted by holesthat are formed through the said checks. The pivot-pins occupy holesthat extend transversely through the said lever-members. For the purposeof enabling each lever-member to be tightened upon the pivotal pin whichoccupies the hole therein, so as to grip and hold the said pin in placeto guard against accidental endwise movement, a slit is made in thelevermember, leading from the exterior surface of the latter to thetransverse hole, and a screw 112 or 122 is provided. to draw the sidesof the slit toward each other, thereby contracting the said hole indiameter.

In the drawings, although not necessarily in the case of all embodimentsof the different features of the invention, the clampinglever 11 makescontact directly with the presserbar 1. See Fig. 3. Movement istransmitted to the primary or clamping-lever 11 from the secondary oractuator-lever 12,

for the purpose of causing the presser-bar to be gripped by the clamp.The two levermembers 11 and 12 constitute ineffect a compound lever. Thearrangement of the said lever-members, and the mode and means 'of theiroperative connection or engagement with each other, may vary more orless in practice. The arrangement shown in the drawings is a convenientone. I usually place the two lever-members in operative connection orengagement with each other, for the purpose of transmitting movementfrom the actuator-lever 12 to the clampinglever 11, by means ofa strut,as 131, Fig. 3, interposed between the said lever-members. The saidstrut is shown formed with enlarged and rounded ends, the lever-membersbeing represented as formed with concave seats receiving the said ends,making knuckle joints. Preferably, oneor each of the seats in thelever-members is proportioned to take in somewhat more than half of thediameter of the corresponding rounded enlarged end of the strut, theouter portions of the seat converging about the enlarged end somewhat soas to clasp the enlargement more than halfway round the same. Thisconstruction, While permittingfree working of the end of the strut inthe seat during action, retains the said end within the seat, andprevents the strut from becoming detached and falling away, eitherduring the operation of assembling the parts or when the parts are beinghandled in setting or adjusting the same. The strut is applied to theseat, formed as just explained, by passing the enlarged end of the strutedgewise into the seat, and also is disengaged therefrom by an edgewisemovement. ,The actuator-lever 12 is operated by means of a tappet 13forming part of a rocker 14, which latter in the present instance, isconveniently arranged at the outer end of head 3, the axis of the saidrocker extending horizontally, parallel with and across the said outerend. The rocker is mounted upon center-screws 15, 15, which are appliedto lugs 31, 31, extending outwardly from the front and rear sides of thehead 3. For the convenient actuation of the rocker in proper timing withthe action of the other working parts of the machine it is in thepresent instance provided with an arm 16, Figs. 1, 2 and 4, which issleeved upon the rocker and made fast thereto by means of clampingscrews16]., 161, Fig. 4, the said arm being joined by means of a link 17,Figs. 2 and 4, to ears projecting from one side" of a collar 18 which ismounted upon a vertically recipro catory bar 19, herein serving as anawl-bar and carrying an awl 191. The bar 19 has connected therewithactuating devices of suitable character, such devices in the presentinstance comprising a link 20 having its lower extremity pivotallyjoined to the collar 18, aforesaid, and'a hub 21, provided with acrank-pin having the upper extremity of the link connected therewith,and mounted upon the operating shaft 22 which is supported in bearingsin the arm or gooseneck 4, all substantially as usual. For the purposeof enabling the time of closing the clamp and be ginning the lift of thepresser-bar, and also the extent of the lift of the presser-bar andpresser-foot, to be regulated when desired, the rocker and tapper 13 aremade angularly adjustable around the axis of motion of the rocker. Thisadjustability is secured by flattening transversely, as shown in Fig. 2,the portion of the rocker 14 against which the inner ends of theclamping-screws 161, 161, bear, and by disposing the said clampingscrewsto make contact with the transversely extending flat surface of therocker at opposite sides, circumferentially, of the middle of the saidsurface. By turning the respective screws more or less the rocker andits tappet may be adjusted angularly' with relation to the arm 16, andthereby the desired timing and extent of lift may be secured. To obviateany tendency to lateral displacement of the actuator-lever 12, therocker and top of the tappet 13 are grooved to receive the saidactuator-lever. An expanding spiral-spring 23, encircling thepresser-bar 1, is confined between the top of the sleeve or block 10 andthe upper portion of the head 3. .It acts expansively with a tendency tomove the clamp downward.

In operation, the rise of the awl-bar serves through the connectionsbetween the same and the rocker to turn the latter in a manner to causethe tappet 13 to swing upwardly. In thus swinging, the said tappetpresses upwardly against the actuator-lever 12. The rise of the clampbeing resisted by the spring 23, the pressure of the tappet acts to turnthe actuator-lever upon its pivotal connection with the cheeks 102, 102,and close the clamp firmly against the presser -bar. Further movement ofthe actuator-lever u on the pivot-pin 121 being then impossi le, theclamp is raised bodily, carrying with it the presser-bar andpresser-foot and compressing the springs 5 and 23. downwardly aftercompleting its upward movement, it lowers the clamp, presser-bar, andpresser-foot, which descend in unison until the presser-foot seatsitself upon the material being operated upon. This relieves the clamp ofthe force exerted by spring 5, and relaxes the pressure of actuatorlever12 against the tappet, the pressure still remaining being only thatwhich is due to the action of spring 23 and to the weight of the clamp.Thereby the hold of the clamp upon the presser-bar is relaxed, and theclamp is permitted to follow the tappet 13 down. In

As the tappet swings order to insure the complete release of thepresser-bar, the actuator-lever is furnished with a heel 123 extendingto the op osite side of the pivotal axis of the actuator ever from theportion of the latter upon which the taptap acts in clamping andlifting. As the parts complete their descent the said heel comes intocontact with an inner portion of the tappet, thereby causing theactuator-lever to be turned so as to open the clamp fully. The actingsurface of the tappet makes rolling contact with the actuator-le ver 12,and as the tappet completes its downward swing the said actuator-levercomes gradually to take bearing against the portion of the tappet at itsaxis of movement, while in the upwardswing of the tappet the lifting ofthe actuator-lever is gradually begun and continued. In consequence, theentire clamp is at all times supported on the tappet, and blows,thumping, etc., resulting from play or lost-motion between the tappetand lever are obviated.

Preferably, the actuator-lever 12 and strut 131 are combined andarranged to act together on the principle of a toggle, in order to gainan increase of power. Still further power issecured by the employment ofthe secondary lever 11, and by causing the strut to engage therewith ata point so situated with respect to the pivotal axis of such lever, andto the radial distance from such axis of the part which makes contactwith the presser-bar, as to give effective leverage. This employment ofa compound lever is of great value, practically, inasmuch as it remediesdeficiencies which exist when the clamp is provided with a simpleactuator-lever or the like. It heretofore has been proposed to employ ina lifting arrangement, in combination with a toggle, a block actuatedthereby and in sliding in an opening in the side of the sleeve or block,to engage with the presserbar. This construction gives an insufficienthold upon the presser-bar for some uses, and is unreliable in its actionin lifting the presserbar, there being a tendency to slip. In case thetoggle were set fine enough to overcome the tendency to slip, the togglewould look and fail to release the clamp so as to permit the latter tolet go. The compound-lever arrangement characterizing my presentinvention enables ample power to be secured 'for perfect action, withoutit being necessary to cause the middle joint of the toggle to ap proachso closely to the line connecting the outermost joints as to occasion atendency to lock.

The operative portion of tappet 13 extends from the axis of motion ofthe rocker toward the presser-bar, and the arm of the actuatorlever thatis engaged by the said tappet extends from the pivot of theactuator-lever in the same direction. This enables the lifting forcewhich is. transmitted from the upw'ardly swinging tappet 13 to act alongvertical lines of transmission at the same side of l the said pivot andaxis, and also of the toggle-joint, as the presser-bar, closely adjacentthe presser-bar. There is, in consequence, very little tendency duringthe lift to spring the presser-bar and cause the same to bind in itsguide-bearings in the head of the machine. Hence, the resistance whichhas to be overcome in raising the presser-bar and presser-foot, and thewear between the presser-bar and its guide-bearings, are not materiallyincreased through this cause. The action, in other words, is renderedeasier than would be the case were the lifting tappet arranged to act atthe opposite side of the pivot and 'aXis aforesaid, the wear and tear ofthe presser-bar and its bearings are much less, and less strain devolveson the parts through which the actuation of the lifting tappet isderived. The arrangement, also, is considerably more compact than it ispossible to make one in which the lifting tappet and arm or leverengaged thereby extend outward from the presser-bar, inasmuch as acertain distance is necessary to be occupied in order to secure the len'th of levers, etc, requisite in attaining t e required power in theclamping action, and in attaining the required length of lift.

While I have herein shown and described the actuating tappet of theclamps as operated by the awl-bar of a sewing-machine, it is equallywithin the principle of my invention to operate the said tappet by meansof the needle-bar in a sewing machine in which the latter is mounted inthe head thereof.

I do not claim herein, per 56, the compound lever or the other broad andleading features which have been described, for the same have been madethe subject of claim in my application filed August 19, 1904, Serial No.221,378.

I claim as my invention 1. In presser-foot lifting mechanism, thecombination with the presser and presserbar, of the clamp provided withthe compound lever acting with multiplied leverage in effecting the gripand'comprising a clamping-lever and an actuator-lever, both carried bythe clamp-body, and means actuating the said actuator-lever and therebyoperating the clamp to grip the bar and lift the presser bar andpresser.

'2. In presser-foot lifting mechanism, the combination with the awl-baror needle-bar, the presser, and the presser-bar, of the clamp providedwith the compound lever comprising an actuator-lever and aclamping-lever, both carried by the clamp-body, and the tappet operatedby the awl-bar or needle-bar and actuating the said actuator-lever tooperate the clamp and lift the presser-bar and.

presser.

3. In presser-foot lifting mechanism, the combination with the awl-baror needle-bar, the presser, and the presser-bar, of the clamp providedwith the clamping-lever and with the toggle carried by the clamp-bodyand actuating the said clamping-lever, and the tappet actuated by theawl-bar or needle-bar and operating the said toggle.

4. In presser-foot lifting mechanism, the combination with the awl-baror needle-bar, the presser, and the presser-bar, of the clamp providedwith the compound lever carried by the clamp-body, and the tappetactuated by the awl-bar or needle-bar and transmitting to the saidcompound lever lifting force which acts along vertical lines at thatside of the pivot of the lever-member engaged thereby which is towardthe presserbar, to thereby actuate the clamp and lift the presser-barand presser.

5. In presser-foot lifting mechanism, the

combination with the awlbar or needlebar,

the presser, and the presser-bar, of the clamp provided with aclamping-lever and a toggle in operative connection with the saidclampinglever, both carried by the clampbody, and the tappet actuated bythe awl-bar or needle-bar and transmitting to the said toggle liftingforce which acts along vertical lines at that side of the toggle-jointor knuckle at which the presser-bar is located.

6. Inv presser-foot lifting mechanism, the combination with the awl-baror needle-bar, the presser, and the presser-bar, of. the clamp having acompound lever carried by the clamp-body, and the tappet operated by theawl-bar or needle-bar and engaging with a member of the said compoundlever to actuate the clamp and move the presser-bar endwise, the saidtappet supporting the clamp at all times.

7. In presser-foot lifting mechanism, the combination with the awl-baror needle-bar,

the presser, and the presser-bar, of the clamphaving a compound leverembracing a clamping-lever and an actuator-lever, both carried by theclamp-body, and a tappet operated by the awl-bar or needle-bar,transmitting force to the actuator-lever at that side of the pivot ofthe actuator-lever at which the presser-bar is located to close theclamp and lift the presser-bar and presser, and supporting the clamp atall times.

In testimony whereof I affix my signature in presence of two witnesses.

HENRY I-I. CUMMINGS.

